This invention relates to a novel compound comprising the reaction product of an O-epoxyalkylated tetrakis (hydroxyphenyl) alkane resin with a phenol. This invention further relates to a method for the production of presensitized, lithographic printing plates and to novel lithographic printing plates obtained thereby. More particularly, this invention relates to a negative-working, water-developable, bi-layer or mono-layer lithographic printing plate comprising a substrate having a hydrophilic surface, said surface being either (a) first coated with a layer of a water-soluble, lithographically suitable, photosensitive, negative-working, aromatic diazo compound and top coated with a layer of the water-permeable, water-insoluble, oleophilic resin layer of the aforesaid reaction product or (b) a homogeneous mixture of the aromatic diazo composition and the aforesaid reaction product in a mono-layer system, such systems both providing a water-developable, negative-working, lithographic printing plate. Upon imagewise exposure, the exposed areas become water-insoluble and development is affected by washing away the unexposed areas with tap water.
The art in the lithographic printing plate area has always had a problem with development of the image. That is, various chemical developing substances are employed which must be discarded usually through community waste removal facilities. Not only are such developers costly to purchase but they also cause pollution problems on being discarded. Thus, a lithographic printing plate which is developable by ordinary tap water is commercially desirable.